1. Field of the Invention
The present invention relates to a covering unit for a motorcycle exhaust system comprising exhaust pipes connected to an engine mounted on a body frame of a motorcycle and extending rearwardly. A muffler is mounted on the with rear end of the exhaust pipes.
2. Description of Background Art
In a motorcycle including exhaust pipes extending to an exhaust port and mufflers, the exhaust pipes are usually protected by a heat insulating cover in order to provide insulation from hot exhaust gases. See Japanese Utility Model Publications No. Sho. 63-32895 and No. Hei 311371.
In order to promote heat insulation of the foregoing covering unit, it is conceivable to protect the exhaust pipes and the muffler of the motorcycle with separate heat insulating covers. The heat insulating cover for the exhaust pipes and that for the muffler are different in size, shape, etc. It is very difficult to join such insulating covers by welding a tightening band or the like in order to make them integral. Therefore, it is inevitable that confronting ends of the heat insulating covers are not joined and remain free.
Usually, the foregoing heat insulating covers are made of thin heat resisting plates. Therefore, when vibrations caused by the operation of the engine or running of the motorcycle are transmitted to the heat insulating covers, beat noise will be generated at the free ends of the heat insulating covers. Further, the free ends of the heat insulating covers will interfere with each other and generate interference noise. Both the beat noise and interference noise will increase traffic noise. In order to overcome this problem, it is necessary to reinforce the heat insulating covers, which may increase their weight and cost. This is a further problem to be solved.